The present invention relates to the manufacture of melt spun polymeric filaments and, in particular, to the application of a finishing liquid to the spun filaments.
The manufacture of melt spun polymeric filaments is typically achieved by extruding a molten polymer, such as polyester, polyamide, etc., through a spinneret and then cooling the filaments thus formed. Therebelow, the filaments are converged and gathered at a guide and delivered to a bobbin or further treatment station. A finishing liquid is applied to the filaments below the quench zone. The finishing liquid may comprise a substance suitable for imparting a desired property to the filaments, such as smoothness, drape, luster, water repellency, flame retardancy, or crease resistance, for example.
The manner in which the filaments are cooled has a significant impact on the resulting quality of the filaments. A typical cooling technique involves a gas quench in which cool air is blown across the filaments as they emerge from the spinneret. In instances where the filaments are extruded in the form of a circular array, it is common to utilize an outflow quench technique in which the filaments are passed downwardly in surrounding relation to an upwardly extending air pipe, the latter being arranged generally coincident with the central axis of the group of filaments. Quench air is directed radially or laterally outwardly through the filament group from an upper, apertured end of the pipe, the air preferably dispersed by a porous sheathing surrounding the apertures. There is thus produced a controlled cooling of the filaments.
In a recent development disclosed in copending application Ser. No. 149,370 of Roland Waite, filed May 13, 1980, a quenching technique has been devised in which quench air is delivered downwardly through the pack and spinneret. This technique has eliminated the elbow below the quenching zone and its accompanying disadvantages.
The application of finishing liquid has heretofore been accomplished, for example, by means of a stationary applicator within which the filaments are gathered. Finishing liquid is caused to flow across the applicator surface and onto the gathered filaments. Another technique involves spraying the finishing liquid onto the filaments which have been gathered at the turning guide. It will be appreciated that the quality of the filaments produced is affected by the uniformity of application of the finishing liquid. The application of the liquid to the filaments when the latter are in a gathered or bunched-up condition is difficult to achieve with the desired uniformity.
It is, therefore, an object of the present invention to minimize or obviate problems of the type discussed above.
Another object of the invention is to provide novel methods and apparatus for the application of finish substance to melt-spun filaments in a more uniform manner.
A further object of the invention is to provide such methods and apparatus without reducing operator accessibility and without hindering filament travel.